Re: aio stress panic on 2.6.11-mm1
From: Andi Kleen
Date: Wed Mar 09 2005 - 06:18:31 EST
Suparna Bhattacharya <suparna@xxxxxxxxxx> writes:
> Any sense of how costly it is to use spin_lock_irq's vs spin_lock
> (across different architectures) ? Isn't rwsem used very widely ?
On P4s cli/sti is quite costly, let's says 100+ cycles. That is mostly
because it synchronizes the CPU partly. The Intel tables say 26/36 cycles
latency, but in practice it seems to take longer because of the
I would assume this is the worst case, everywhere else it should
be cheaper (except perhaps in some virtualized environments)
On P-M and AMD K7/K8 it is only a few cycles difference.
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